Drill stem tester



Nov. 19, 1957 w. D. MoUNcE 2,813,587

DRILL STEM `'LESTER `Filed April '7, 1955 2 sheets-sheet 1 w. D. MoUNcEDRILL vSTEM TESTER Nov. 19, 1957 2 Sheets-Sheet Filed April 7, 1955INVENTOR. Wh/'fm an D.. Mou/Ice,

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ATTORNEY DRILL STEM TESTER Whitman D. Mounce, Houston, Tex., assigner,by mesne assignments, to Esso Research and Engineering Com pany,Elizabeth, N. J., a corporation of Delaware Application April 7, 1955,Serial No. 499,949

8 Claims. (Cl. 166-103) This invention relates to the art of takingsamples of the uid present within a subsurface formation. Moreparticularly this invention relates to apparatus for taking a samplefrom a subsurface formation while drilling a borehole.

During the drilling of la borehole various factors such as an increasein the drilling rate, a flow of oil or loss of mud returns indicate thata drill stem test of the formation fluid is desirable. The sooner thetest can be made the more useful the results obtained from the test willbe. However, because of the delay associated with present testingmethods and apparatus the test must be deferred until the drill pipe isremoved from the borehole and a separate testing instrument is loweredinto the borehole to the proximity of a formation to be tested.

My new apparatus and method provides a means for taking a drill stemtest when it is felt that such a test is advisable, without requiringthat the drill pipe be removed from the borehole.

Briefly described, my new apparatus for taking a drill stem testconsists of a string of pipe which has attached to its lower end adrilling bit. During drilling operations, mud is flowed under pressurethrough the string of pipe and the drilling bit and up the annulusbetween the string of pipe and the side surface of the borehole. When itis desirable to take a drill stem test the flow of mud is temporarilydiscontinued and a weight such as a go-devil is dropped through thestring of pipe. The go-devil actuates a plunger valve to permit the flowof fluid from a fiuid reservoir contained wherein the drill stem to aninflatable packer thus isolating the subsurface formation from which itis desired to obtain test fluids from the rest of the hole. Means areprovided for effectuating the flow of the well fluids into the drillpipe. A swab may be lowered into the drill pipe to bring some of thesample fluids up to the surface. Means are also provided for removingthe weight or go-devil with such removal permitting the resumption ofdrilling of the borehole without necessitating the removal of thedrilling tool.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings in which:

Fig. 1 is a longitudinal view of the lower part of the string of pipeand the drilling bit;

Fig. 2 is a longitudinal sectional view showing, during drillingoperations, the position of the valve means utilized for inflating anddeflating the packer.

Fig. 3 is a longitudinal sectional view of the valve means showing itsposition after a go-devil has been dropped into the drill pipe to permitthe inflation of the packer and the taking of a fluid sample from thesubsurface formation;

Fig. 4 is a section taken through 4-4 of Fig. 3;

Fig. 5 is a section taken along 5-5 of Fig. 3; and

Fig. 6 is a longitudinal sectional view showing another form of go-devilwhich might be utilized in my well testing system.

States Patent 0 2,813,587 Patented Nov. 19, 1957 Referring to thedrawings and more particularly to Fig. 1 numeral 10 represents aborehole which has been drilled into the subsurface formations such asthe forma-l tions shown at 11 and 12. Formation 13 represents a poroussubsurface stratum which has been penetrated by the drilling toolresulting in loss of returns or a fas/ter rate of drilling or a showingin the drilling mud of oil or other factors which might indicate a drillstem test is advisable. Figs. 1 through 5 show the elements of theapparatus which are utilized while the test is being made. As shown inFig. l, packer 14 is in the inflated position thus sealing offsubsurface formation 13. The. apparatus includes a string of pipe 15which has connected thereto a drill collar 16. Connected at the lowerend of the drill `collar is a drilling bit 17. Also included in theapparatus is a packer setting fluid reservoir 18 which may consist of adeformable bag. A valve means 19 is provided to control a flow of packersetting fluid between the packer setting fluid reservoir 18 and packer14 for infiating and deflating packer 14. In Fig. l a go-devil 20 isshown in its position after drilling operations have been discontinuedand the go-devil 20 has been dropped down the drill pipe 15 to engage aplunger 21 included in valve means 19. When plunger 21 has beendepressed, formation fluids enter a fluid passageway leading from mudpassages in the drill bit 17 up to a fluid passageway contained withingo-devil 20 and then into the drill stem 15. The mud which is within thefluid passageway and the drill stem is first removed by continuously.lowering and raising a swab 22 and then the formation fluids will appearwithin the drill stem 15 and be removed to the surface. After the testhas been made the swab which has an overshot 23 therein is lowered downthe drill stem 15 to engage retrieving head 24 of the go-devil. When theswab is removed to the surface the go-devil 20 is also removed thusreleasing valve means 19 resulting in the deflation of the packer 14 andpermitting the resuming of drilling operations.

Fig. 2 shows in more detail the packer setting fluid reservoir 18 andthe valve means 19. The position of valve means 19 shown in Fig. 2 isthe position valve means 19 assumes during drilling operations. Duringdrilling operations mud is pumped down the drill stem 15 and throughfluid passageway 25 to the drill bit 17 (see Fig. 1) and thence up theannulus between. the string of pipe and the side surface of the borehole1li. Some of the mud pressure is also conducted through passageway 26 tothe underside of a plunger 21, which plunger is an important element ofthe valve means 19. Mud pressure is also conducted through passageway2'7 against a fluid reservoir 18 which may consist of a deformable bag.De* formable bag 18 is filled with a fluid which is utilized to inflatethe packer 14 of Fig. l. Plunger 21 has out therein a keyway 2S whichrides along a key 29. Plunger 21 is biased upwardly (as shown in Fig. 2)by a biasing means 30 such as a compression spring. 1n addition to theforce of compression spring 3i) the pressure transmitted throughpassageway 26 to the underside 31 of plunger 21 helps to maintainplunger 21 in its upper position despite the pressure of the drillingmud. Plunger 21 has a packer setting fluid inlet 32 and a packer settingfluid outlet 33 with a hollowed out portion 34 serving to conduct fluidfrom packer setting fluid inlet 32 to packer setting fluid outlet 33. Acheck valve 35 is included in the fluid passageway 34 to allow the fiuidflowing through hollowed out portion 34 to ow in one direction only. Apassageway 36 leads from deformable bag 18 and then branches out intotwo passageways 37 and 38. Another fluid passageway 39 is providedwithin the drill collar 16 for conducting packer setting fiuid passedthrough valve means 19 to the inflatable packer 14. Rubber O-rings 40are provided in grooves 41 of plunger 21 to prevent the escape of fluidsaround plunger 21.

During drilling operations mud pressure is also exerted throughpassageway 27 against the deformable bag member 1S. However, plunger 21is in a position so that no packer setting fluid flows into packersetting fluid inlet 32 whereas any fluids which may be present in packer14 and fluid passageway 39 are permitted to flow through check valve 3S,fluid outlet 33 and fluid conducting means 38 into deformable bag 1d.

Fig. 3 shows the position of the deformable bag lil and valve means 19after a go-devil 2t) has been dropped down drill pipe As shown in Fig. 3go-devil 20 has yengaged the head dd of plunger 21 and moved plunger 21downwardly against the bias of coil spring Btl. The head portion 45 ofthe go-devil 2li is formed so as to rest upon a seat member 46 formedwithin drill collar 16. The packer setting fluid inlet 32 is nowdisposed opposite to passageway 37 and the packer setting fluid outlet33 is disposed opposite the passageway f7 which connects with passageway39 leading to the inflatable packer 14. Hence after go-devil has beendropped on the seat 46 fluid pressure may then be applied by the mudpump at the surface around go-devil 2li through grooves 48 out in drillstem 1d and thence through passageway 27 against the deformable bag 1S.rlhis application of mud pressure effectuates the flow of packer settingfluid through passageway 36, inlet 32, check valve 35, outlet 33,passageway 47' and passageway 39 into packer 14. Check valve 35 preventsany flow of fluid from packer 14 back into reservoir 18. Mud fluidpressure is prevented from being applied through fluid passageway bymeans of gaskets 49 which provide for a fluid-tight engagement ofgo-devil 20 with the seat 46. Mud fluid pressure is also prevented fromentering fluid passageway 25 through ports Sil formed in go-devil 2l) bya valve S1 which may consist of a spherical ball.

After the packer fflhas been inflated, swab 22 (see Fig. l) is lowereddown into drill stem 15)'. By continuously lowering and raising swab 22the mud within the drill stein is removed. The pressure within thesubsurface formations forces the formation fluid up passageway 25 andinto passageway 52 which is formed within the head 45 of go-devil 2li.rl`he formation fluid will unseat valve 5]. and flow out of ports Si)and through grooves 48 into the drill stem l5. The flow of thesubsurface formation fluid is aided by suction created by the raisingand lowering of swab 22. The swab 22 may then be raised to the surfaceand the formation fluid, gathered by said swab 22, l

examined. Swab 22 is then again lowered down the drill stem 15 and theovershot 23 grasps retrieving head 24 to allow for the pulling out ofgo-devil 2d.

After go-devil 20 has been unseated from seat tl-6 by overshot 23plunger 21 will again be biased upwardly by compression spring allowingthe packer setting fluid to flow from packer 1d through fluid passageway39, packer setting fluid inlet 32, check valve 35, packer setting fluidoutlet 33 and fluid conductors 3S and 36 to reservoir 1li. The mudpressure may then be again applied through fluid passageway 2S to thedrill bit f7 and drilling operations resumed.

A construction of go-devil which might be utilized in place of a godevilsuch as that shown in Fig. 3 is shown in Fig. 6 wherein like numeralsare used to refer to like parts. As shown in Fig. 6, a passageway 53 isbored through the entire length of go-devil 54 so the well fluidsflowing into passageway 52 will flow entirely through the go-devil 5dand on np into the drill stem 15.

During drilling, when it is thought advisable to take a drill stem test,a gro-devil is dropped down the string of pipe and iinpinges valve means19 and forms a fluid tight engagement with seat d6. The position ofvalve means 19 then permits the packer 1d to be inflated by theapplication of mud pressure against deformable bag 1S. The applicationof mud pressure is ceased after packer 14 becomes fully inflated. SwabZ2 is then lowered down the drill string 15 and continuously raised andlowered thereby swabbing out the mud remaining in the apparatus. Theformation fluid then begins to flow through bit 17, passageway 25,passageway 52 and into the drill string. After the formation fluid hasbeen removed from swab 22, the swab is lowered to engage retrieving head24 of go-devil 20 and remove go-devil 20 from the drill stern 15. Uponthe removal of go-devil 2f) the plunger 21 will be moved upwardly bycoil spring 3d thus permitting the deflation of packer 14. Any earthformation fluid which remains in the drill pipe can then be brought outby reversing the circulation of the mud so that the mud is pumped downthe annulus between the drill pipe and the side surface yof the boreholeand up through fluid passageway 25. The apparatus is then ready for thecontinuance of drilling operations.

Although l have described my invention with a certain degree ofparticularity, it is understood that the present disclosure has beenmade only by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

l claim:

l. ln apparatus for making a drill stem test: a drill pipe; a drillingbit having at least one orifice therein attached to said drill pipe,said drill pipe having a fluid passage to said orifice in the drillingbit; an inflatable tubular packer on said drill pipe adapted to seal offthe subsurface area to be tested; a flexible bag containing fluid withinsaid drill pipe with means for subjecting said flexible bag to mud-pumppressure; a fluid passageway within said drill pipe to conduct fluidbetween the bag and the packer, valve means in said fluid passage tocontrol the flow of fluid between said flexible bag and said packer;said valve means in one position preventing the flow of fluid from saidflexible bag to said packer but permitting flow in another position fromsaid packer to said flexible bag; a weight adapted to engage and movesaid valve means to permit the flow of fluid from the flexible bag tothe packer thereby inflating said packer, said weight having a lluidpassage adapted to coincide with the fluid passage to said drilling bitwhen the weight engages the valve means; and a valve in said weightfluid passage adapted to permit the flow of well fluids into said drillp2. In apparatus for making a drill stem test: a drilling bit having afluid passageway therethrough; a hollow drill stern; said drilling bitbeing connected to the lower end of said drill stern; a deformable bagwithin said drill stem containing liquid; means in said drill stem forsubjecting said deformable bag to mud flow pressure; a packer; liquidconducting means in said drill stem interconnecting said deformable bagand said packer; valve means in said liquid conducting means forcontrolling the flow of liquid between said deformable bag and saidpacker, said valve means being in a first position to obstruct the flowof liquid from the deformable bag to the packer; a go-devil adapted tobe dropped upon and move said valve means to a second position so as topermit the flow of liquid to said packer thereby inflating said packer,said go-devil having a test fluid passageway and valve means fortransmitting test fluid flowing into said drilling bit passageway undersubsurface pressure from said drilling bit passageway to said hollowdrill stem.

3. ln apparatus for making a drill stem test: a string of pipe adaptedto be lowered into a borehole; a drill bit connected to the lower end ofsaid string of pipe; said string of pipe having a seat formed therein; afluid passageway in said string of pipe; means for flowing mud underpressure through said string of pipe and through said fluid passagewayand out of said drill bit during drilling; a packer located on saidstring of pipe below said seat, said packer being deflated duringdrilling; a deformable bag filled with packer setting fluid within saidstring of pipe; a plunger also located Within said string of pipe; saidplunger having a packer setting fluid inlet and a packer fluid outletwith a fluid passageway therein interconnecting said inlet and saidoutlet; first means in said string of pipe adapted to conduct packersetting fluid from the deformable bag to said fluid inlet; biasing meansarranged in said string of pipe to bias said plunger to a position so asto maintain the fluid inlet out of coincidence with said conductingmeans during drilling; a go-devil adapted to be dropped upon saidplunger to thereby move said plunger against said biasing means to causesaid packer setting fluid inlet to coincide with said rst fluidconducting means and cause said packer setting fluid outlet to coincidewith a second fluid conducting means in said string of pipe leading tosaid packer, said go-devil seating on said seat; means in said string ofpipe for subjecting said deformable bag to mud pressure to therebyinflate said packer; means connected to said go-devil so as to provide aHuidtight connection between said fluid passageway in the string of pipeand a fluid passageway formed in the go-devil thereby permitting thefluids within the formation being tested to be flowed through the drillbit and up through the fluid passageway in the string of pipe.

4. In apparatus for making a drill stem test: a string of pipe adaptedto be lowered into a borehole; a drill bit connected to the lower end ofsaid string of pipe; said string of pipe having a seat formed therein; afluid passageway in said string of pipe; means for flowing mud underpressure through said string of pipe and through said fluid passagewayand out of said drill bit during drilling; a packer located on saidstring of pipe below said seat and above said drill bit, said packerbeing deflated during drilling; a packer setting fluid reservoir in saidstring of pipe; a plunger also located within said string of pipe, saidplunger having a packer setting fluid inlet and a packer fluid outletwith a fluid passageway therein interconnecting said inlet and saidoutlet; first means in said string of pipe adapted to conduct packersetting fluid from the reservoir to said fluid inlet; biasing meansarranged in said string of pipe to bias said plunger to a position so asto maintain the fluid inlet out of coincidence with said first fluidconducting means during drilling; a godevil adapted to be dropped uponsaid plunger to thereby move said plunger against said biasing means tocause said packer setting fluid inlet to coincide with said first fluidconducting means and cause said packer setting fluid outlet to coincidewith a second fluid conducting means in said string of pipe leading tosaid packer, said godevil seating on said seat; means in said string ofpipe for forcing fluid from said packer setting fluid reservoir to saidpacker thereby inflating said packer; means connected to said go-devilto provide a fluid-tight connection between said fluid passageway in thestring of pipe and a fluid passageway formed in the ,go-devil when saidgodevil seats on said seat thereby permitting the fluids within theformation being tested to be flowed through the drill bit and up throughthe fluid passageway in the string of p1pe.

5. In apparatus for making a drill stem test provided with a drill pipehaving a fluid passage therethrough and having a drill bit attachedthereto: an inflatable packer connected into said drill pipe; a flexiblebag containing fluid within said drill pipe with means for subjectingsaid flexible bag to mud-pump pressure; a fluid passageway between saidbag and said packer; valve means within said passageway, said Valvemeans being adapted to control the flow of fluid between said flexiblebag and said packer; a Weight movable through said drill pipe andengageable with said valve means to move said valve means from a firstto a second position to permit the flow of fluid from the flexible bagto the packer thereby intlating said packer, said weight having a fluidpassage adapted to coincide with the fluid passage in the drill pipewhen the weight engages the valve means; a valve in said weight fluidpassage adapted to permit the flow of well fluids into said apparatus.

6. Apparatus for use in a drill stem test comprising, a pipe stringhaving a fluid passageway therethrough, a seating surface in said pipestring, an inflatable packer arranged on said pipe string below saidseating surface, a sealed fluid reservoir in said pipe string, saidreservoir being interconnected iluidly with said packer by a fluidconducting means, said fluid reservoir being deformable, means forconducting fluid pressure against said reservoir to inflate said packer,a Valve arranged in said fluid conducting means and normally in closedposition for controlling flow of fluid from the reservoir to the packer,and a go-devil movable through said pipe string and seatable upon saidseating surface to engage said valve to move said valve from a closedposition preventing fluid flow from the reservoir to the packer to openposition permitting fluid flow from the reservoir to the packer toinflate the packer.

7. Apparatus for use in a drill stem test comprising, a string of pipehaving a fluid passageway therethrough, said pipe string having a seatformed therein, an inflatable packer in said pipe string, a sealedreservoir for inflation fluid in said pipe string, said reservoir beinginterconnected fluidly with said packer by a fluid conducting means,said fluid reservoir being deformable, means for conducting fluidpressure against said reservoir to inflate said packer, a valve in saidfluid conducting means normally in closed position for controlling theflow of inflation fluid from the fluid reservoir to the packer, ago-devil movable through said pipe string to engage said valve and tomove said valve from closed position preventing fluid flow from thereservoir to the packer to open position permitting the flow ofinflation fluid to said packer, said go-devil being constructed to seatitself upon said seat in fluid-tight engagement, said go-devil having afluid passageway therein communicating with said pipe string fluidpassageway, and a valve in said go-devil fluid passageway forcontrolling the flow of fluid through said go-devil fluid passageway.

8. Apparatus for use in a drill stem test comprising, a pipe stringhaving a fluid passageway therethrough, a seating surface in said pipestring, an inflatable packer arranged on said pipe string below saidseating surface, a sealed fluid reservoir in said pipe string, saidreservoir being interconnected fluidly with said packer by a fluidconducting means, said fluid reservoir being deformable, means forconducting fluid pressure against said reservoir to inflate the packer,a valve arranged in said fluid conducting means normally in closedposition for controlling flow of fluid from the reservoir to the packer,and a godevil movable through said pipe string and seatable upon saidseating surface, said Valve moving from closed position preventing fluidflow from the reservoir to the packer to open position permitting fluidflow from the reservoir to the packer, upon the seating of said go-devilon said seating surface, to interconnect fluidly said reservoir and saidpacker to inflate the packer.

References Cited in the file of this patent UNITED STATES PATENTS2,497,185 Reistle Feb. 14, i950 2,582,530 Daetwiler Jan. 15, 19522,663,545 Grable Dec. 22, 1953

